Present day implantation of artificial materials that contact blood occurs frequently despite the paucity of knowledge concerning the biochemical and biophysical interactions of foreign surfaces with blood. Increased use of these prosthetic devices is limited by thrombogenic reactions. The platelet a major blood reactant activated by any non-endothelial surface-may be retained or returned to the circulation in an altered state. During this process, the platelet may accelerate coagulation factor activation and promote thrombosis. None of these altered platelet states is desirable. There is a considerable amount of evidence to suggest that platelet activation can be modified by environmental fatty acids. We propose to determine which of the fatty acids contained within albumin and adsorbed to a foreign surface can minimize platelet activation. Goat albumin will be defatted and refatted with a variety of fatty acids and prostaglandin analogues. These albumin variants will be used in an established, sensitive, continuously monitored ex vivo goat model for testing thrombogenecity. We will measure non-invasively early platelet retention and increased turnover in the shunt and animal, and correlate these changes with later changes in fibrinogen retention and turnover as well as with post-mortem analyses of the animals. Our intent is to broaden the range of acceptable biomaterials, to investigate the potential regulatory role of a variety of fatty acids in coagulation factor and platelet activation, and to utilize this new knowledge to prolong the useful time that devices can contact blood continuously.